The EPigenetic Consequences in Children of Intravenous vs Volatile Anaesthesia for Surgery (EPIVA) - A Randomised, Feasibility Trial

There remains uncertainty about the impact that general anaesthesia may have on many different processes and systems for a child. The effect on the developing brain is an area that has received growing attention over the last decade. Pre-clinical studies, including those looking at cells and animal models, have demonstrated the harmful effect that anaesthetic drugs can cause in nerve cells. Large studies of children have suggested that early age exposure to anaesthetic drugs may impact cognitive and behavioural outcomes however, although this has not been a universal finding.

In 2016 the United States Food and Drug Administration (FDA) issued a warning regarding the use of anaesthetic drugs for children aged under 3 years, with the highest level of concern afforded to those who have prolonged and/or repeat exposures, showing the importance of this topic. This importance is further highlighted by the annual paediatric anaesthetic caseload - more than half a million children have an anaesthetic each year in the UK. There have been pre-clinical studies that have suggested that the way in which anaesthetic drugs can impact on neurodevelopment and cognition is through modifying the way in which genes are expressed by altering signals on DNA (epigenetics). This research aims to explore whether these changes in signals in DNA (epigenetic changes) can be seen in children undergoing anaesthesia and whether this is impacted by the type of anaesthetic given.

To do this, the trial has been designed as a randomised, clinical, feasibility trial in which participants undergoing hypospadias surgery will be randomised to one of the two anaesthetic maintenance approaches that are used routinely in clinical practice: intravenous or inhalational. Baseline data, including demographics, will be collected. On the day of their surgery, participants will receive maintenance of anaesthesia either through inhalational anaesthesia or intravenous anaesthesia according to allocation at randomisation - participants and their legal representatives will be blinded to group allocation and subsequent analysis will be performed with blinding to allocation. The participant will then be anaesthetised, and a baseline blood sample will be taken from the cannula that is routinely inserted into a vein to give medication to the patient. If this is not possible, the sample will be taken from a peripheral site. After the surgical procedure is complete and before the participant wakes up from general anaesthesia, a second blood will be taken. Blood will then undergo laboratory analysis including epigenetic, biochemical, haematological, and redox.

This trial has been designed as a feasibility trial to evaluate whether a larger scale trial looking at anaesthesia and surgery in relation to changes in markers on DNA (epigenetics) is both possible, and of value. Currently there have been no published studies looking at whether general anaesthesia can cause epigenetic changes in children, and whether the type of anaesthetic given has an impact on any changes present. There is significantly less published research in children as it necessitates many additional considerations; this is part of the rationale for this study being designed as a feasibility trial with the primary objective of assessing and determining the feasibility of conducting a paediatric perioperative epigenetics study in which participants are randomised to two methods of maintaining anaesthesia for surgery. Alongside measures such as recruitment and retention rate, screening numbers, protocol compliance figures, this objective will incorporate feedback on acceptability for participants and clinical staff, the success of the data management system used, and if any additional resources are required.

It has also been designed to address the secondary objectives of exploring whether anaesthesia and surgery are associated with epigenetic changes in whole blood, whether the strategy used to maintain anaesthesia impacts any epigenetic changes observed, and to identify which genes, pathways, and functional biological processes, may potentially be involved.